I took it to be a function of the normal muscles. I still think so.
Besides, strongyloides are very tiny...like 1/10 of an inch in adulthood. I would think that the larva must be microscopic.
As I understand it, they try to get themselves coughed up from the lungs, and swallowed into the stomach, so they may spend their adulthood in one's intestines.
I try to spit every bit of mucus and phlegm that comes into my mouth, just in case.